1. Field of the Invention
The present invention relates to electrical connectors, and, more particularly, to a connector for selectively connecting an insulated conductor to a conductive terminal post, for example, of the type commonly found in automotive ignition systems for connecting a wire to a spark plug.
2. Description of the Related Art
Automotive ignitions systems frequently have a cable or similar insulated conductor connecting a distributor terminal to a corresponding spark plug. The spark plug characteristically has a central terminal post to which one end of the cable connects. The plug body is grounded to the engine head or block. The spark plug end of the cable may have an electrical connector or terminal that is crimped to the cable contacting the cable conductor, and have a free end for selectively gripping the central terminal post of the spark plug. The distributor end of the cable may also have an electrical connector crimped to the cable contacting the cable conductor, and a free end for selectively gripping a distributor post. The connector may be of a straight variety where the cable extends away from the terminal post generally in alignment with the terminal axis, or may be of an orthogonal variety where the cable extends away from the post generally perpendicular to the axis of the post. The distributor may have a terminal post to which the distributor end of the cable connects, or may have a cavity into which a conductive sleeve, that is crimped to the cable end and contacts the conductor, may be inserted. Spark plug connectors are frequently, but not necessarily, of the straight variety, and distributor terminal connectors are typically, but not always, of the orthogonal variety.
It is important that the connector be relatively easily removed from the terminal post for engine maintenance, yet securely grip the terminal post both to achieve good electrical contact and to prevent inadvertently disconnecting from the terminal post. Forming the connector from thinner material facilitates manufacture and reduces material costs, however material strength and resilience are reduced, and there is a correlative reduction in the radially inward forces which serve to retain the connector on the post.
It is known to provide the end of the connector that is to be secured to the spark plug terminal post as a cylindrical body with a longitudinal slit, with one or more holes or openings in the cylindrical body, on opposite sides of the longitudinal slit. The longitudinal slit allows the cylinder walls to push outwardly as the connector is pushed onto the spark plug terminal post. A band surrounds part of the cylindrical body, spanning the longitudinal slit, and has hemispherical dimples that project through the openings of the cylindrical body to engage the spark plug terminal post. While connectors of this type have worked to some degree of satisfaction, the force required to insert the spark plug terminal post into the connector is relatively high. The resistance encountered can falsely imply that the terminal is fully inserted, leading to a faulty connection between the conductor and the spark plug.
What is needed in the art is a spark plug terminal connector for automobile ignition systems that requires reduced insertion force for connecting the terminal to a spark plug terminal post, without substantial reduction in the retention force of the terminal on the spark plug terminal post.
The present invention provides a connector requiring less force than previous connector designs for engaging a terminal post, through the use of ramp-like surface for sliding the connector onto the terminal post.
The invention comprises, in one form thereof, an electrical connector for connecting a conductor to a generally cylindrical conductive terminal post. A first connector portion has a cylindrical shell of about the same axial length as the terminal post. The shell has an open forward end and an inner surface with an inner circumference to completely encircle the terminal post. The shell has at least one rectangular opening therein. A band encircles at least a portion of the shell, and includes at least one inwardly extending dimple shaped for receipt in the opening. The dimple has a substantially flat, ramp-like forward surface.
In another form thereof, the invention provides an electrical connector for connecting a conductor to a generally cylindrical conductive terminal post, with a first connector portion having an open-ended cylindrical shell with an opening disposed therein. A band surrounds at least a portion of the shell, and has an inwardly extending dimple received in the opening. The dimple is of pyramid shape.
In a further form thereof, the invention provides an electrical connector for engaging a spark plug terminal post, to connect the terminal post to an electrical conductor. The connector includes a cylindrical shell for surrounding the terminal post. The shell has an open forward end and an inner surface. A dimple projects inwardly of the shell inner surface, and has a ramp-like forward surface.
An advantage of the present invention is providing a connector for a terminal post requiring less force for engaging the connector with the terminal post.
Another advantage is providing a connector for electrically connecting a conductor to a spark plug that requires less force for attaching while maintaining adequate connection after attachment.